What happened
On the evening of the accident, flight IH703 was operating a scheduled domestic service from Pescantara Airport to Rome-Ciampino. The aircraft type was an IFR flight climbing to flight level 100. During the transit, the pilot initially diverted south of the direct path to avoid significant cloud cover and requested radar assistance from the Pescara defense radar.
As the flight progressed, the crew encountered difficulties with navigational equipment. The pilot reported that the radio compass was malfunctioning, making it difficult to tune the Rome NDB. While the aircraft was near Mount Cavo, the pilot reported seeing ground antennae; however, shortly thereafter, visual contact with the ground was lost. Due to the suspected failure of the radio compass, the pilot requested a heading toward the Ostia VOR. At 1835 hours, after being cleared to 6,000 feet, the pilot indicated that the VOR was providing unreliable data and stated an intention to fly a heading of 270 degrees over the sea. This was the final communication received from the aircraft.
The wreckage was later located on a steep incline on the southeast side of Mount Serra Alta at an altitude of 1,630 meters. The accident resulted in eight fatalities.
Findings
Investigations into the crash identified several contributing factors. The pilot made critical errors in estimating the aircraft's position, which led to the misidentification of ground lights and landmarks. These errors caused the pilot to incorrectly judge the reliability of the onboard radio and navigation systems.
In an attempt to maintain visual contact with the terrain, the pilot requested and executed descents that ultimately led to the collision with the mountain. The investigation also noted adverse weather conditions during the final segment of the flight, as well as a failure by the crew to notify air traffic control of deviations from the filed flight plan. The accident was attributed to a combination of navigational errors, equipment uncertainty, and difficult environmental conditions.